Expandable interbody

Abstract

In various aspects, an expandable implant for use in a surgical procedure includes a distal cage, a proximal cage mechanically connectable with the distal cage, a top expandable assembly, and a bottom expandable assembly. Each of the top and bottom expandable assemblies have a distal portion in communication with a surface of the distal cage and a proximal portion in communication with a surface of the proximal cage. The expandable implant is expandable firstly in a medial-lateral direction, secondly in a lordotic (e.g., angular) direction, and thirdly a cranial-caudal direction. Additionally, the expandable implant may be diagonally symmetrical about a longitudinal axis of the expandable implant.

What is claimed: 
     
         1 . An expandable implant for use in a surgical procedure, the expandable implant comprising:
 a distal cage;   a proximal cage opposite the distal cage;   a drive screw connecting the distal cage to the proximal cage;   a top distal pivot slidable along a top surface of the distal cage;   a bottom distal pivot slidable along a bottom surface of the distal cage, the bottom surface opposite the top surface;   a top proximal pivot slidable along a top surface of the proximal cage;   a bottom proximal pivot slidable along a bottom surface of the proximal cage, the bottom surface opposite the top surface;   a top pair of endplates, each top endplate having a proximal end slidable along a surface of the top proximal pivot,
 the proximal end defining a proximal channel for slidably receiving a projection of the top proximal pivot, 
   each top endplate also having a distal end slidable along a surface of the top distal pivot, the distal end defining a distal channel for slidably receiving a projection of the top distal pivot,   a first endplate of the top pair of endplates connected to a hook portion of the bottom distal pivot when the expandable implant is in a collapsed state; and   a bottom pair of endplates, each endplate having a proximal end slidable along a surface of the bottom proximal pivot,
 the proximal end defining a proximal channel for slidably receiving a projection of the bottom proximal pivot, 
   each bottom endplate also having a distal end slidable along a surface of the bottom distal pivot, the distal end defining a distal channel for slidably receiving a projection of the bottom distal pivot,   a first endplate of the bottom pair of endplates connected to a hook portion of the top distal pivot when the expandable implant is in the collapsed state; and   wherein the expandable implant is expandable firstly in a medial-lateral direction, secondly in a lordotic direction, and thirdly a cranial-caudal direction.   
     
     
         2 . The expandable implant of  claim 1 , wherein the distal cage comprises:
 a body defining a bore for engaging a distal end of the drive screw and having the top surface and the bottom surface opposite the top surface, and   wherein the top surface has a top ramp and a top slot for engaging the top distal pivot and the bottom surface has a bottom ramp and a bottom slot for engaging the bottom distal pivot.   
     
     
         3 . The expandable implant of  claim 2 , wherein the body has a substantially diamond shape. 
     
     
         4 . The expandable implant of  claim 2 , wherein the top surface tapers toward the bottom surface, the top surface tapering in a direction opposite the top ramp. 
     
     
         5 . The expandable implant of  claim 2 , wherein the bore comprises a first threading to match a distal threading of the drive screw. 
     
     
         6 . The expandable implant of  claim 1 , wherein the top distal pivot comprises a body having:
 a top surface;   a first sidewall extending from the top surface and having the hook portion for engaging the distal end of the first endplate of the bottom pair of endplates, a bottom edge of the first sidewall having an edge ramp for slidably engaging the top surface of the distal cage,   the edge ramp comprising a straight portion and a curved portion, the straight portion of the edge ramp parallel to the top surface of the distal cage when the expandable implant is expanded in the lordotic and cranial-caudal directions; and   a second sidewall extending from the top surface opposite the first sidewall,   the top surface, the first sidewall, and the second sidewall together defining an open bottom opposite the top surface,   the first and second sidewalls engaging a slot defined by the top surface of the distal cage, and   the open bottom having a ramp slidable along the top surface of the distal cage.   
     
     
         7 . The expandable implant of  claim 6 , wherein the bottom distal pivot is identical to the top distal pivot and symmetrically oriented about a longitudinal axis of the expandable implant. 
     
     
         8 . The expandable implant of  claim 1 , wherein the top pair of endplates comprises the first endplate and a second endplate, each endplate comprising:
 a body extending between the proximal end and the distal end;   an extension at the proximal end for engaging with the proximal end of each endplate of the bottom pair of endplates; and   a cut-out defined in a medial edge of the body,   the distal end of the body defining a distal slot to slidably engage the top surface of the distal pivot, and   the proximal end of the body defining the proximal channel to slidably receive the projection of the top proximal pivot,   the distal end of the body defining the distal channel to slidably receive the projection of the top distal pivot, and   each endplate moveable in the medial-lateral direction.   
     
     
         9 . The expandable implant of  claim 8 , wherein the bottom pair of endplates comprises the first endplate and a second endplate, each of the endplates being identical to the top endplates and being diagonally symmetrically arranged about the longitudinal axis of the expandable implant. 
     
     
         10 . The expandable implant of  claim 1 , wherein the top proximal pivot comprises:
 a body having the projection for slidably engaging the proximal ends of each endplate of the top pair of endplates;   lateral wings extending from the body, the lateral wings slidably engaging a portion of the top surface of the proximal cage; and   a ramp on an underside of the body, the ramp for sliding along the top surface of the proximal cage.   
     
     
         11 . The expandable implant of  claim 10 , wherein the bottom proximal pivot is identical to the top proximal pivot and symmetrically oriented about the longitudinal axis of the expandable implant. 
     
     
         12 . An expandable implant for use in a surgical procedure, the expandable implant comprising:
 a distal cage;   a proximal cage opposite the distal cage;   a drive screw connecting the distal cage to the proximal cage;   a top expandable assembly, the top expandable assembly having:   a distal portion in communication with a top surface of the distal cage,   a proximal portion in communication with a top surface of the proximal cage,   a first top endplate having a distal end in connection with the distal portion and a proximal end in connection with the proximal portion, and   a second top endplate adjacent to the first endplate, the second endplate having a distal end in connection with the distal portion and a proximal end in connection with the proximal portion; and   a bottom expandable assembly, a distal portion of the bottom expandable assembly in communication with a bottom surface of the distal cage and a proximal portion of the bottom expandable assembly in communication with a bottom surface of the proximal cage,
 the bottom surface of the distal cage opposite the top surface and the bottom surface of the proximal cage opposite the top surface, 
 the distal portion of the top expandable assembly comprising a hook for mechanically connecting to a distal end of a first bottom endplate of the bottom expandable assembly, and 
 the distal portion of the bottom expandable assembly comprising a hook for mechanically connecting to the distal end of the second top endplate of the top expandable assembly, 
   the expandable implant is expandable first in a medial-lateral direction, second in a lordotic direction, and third in a cranial-caudal direction.   
     
     
         13 . The expandable implant of  claim 12 , wherein the bottom expandable assembly is identical to the top expandable assembly and disposed diagonally symmetrical about the longitudinal axis of the expandable implant. 
     
     
         14 . The expandable implant of  claim 12 , wherein a proximal extension of the first bottom endplate is mechanically engaged with a proximal extension of the first top endplate, such that the first bottom endplate and the first top endplate move together in the medial-lateral direction. 
     
     
         15 . The expandable implant of  claim 12 , wherein a proximal extension of a second bottom endplate is mechanically engaged with a proximal extension of the second top endplate. 
     
     
         16 . An expandable interbody for use in a surgical procedure, the expandable interbody comprising:
 a distal cage;   a proximal cage in mechanical communication with the distal cage;   a top distal ramp slidable along a top surface of the distal cage;   a bottom distal ramp slidable along a bottom surface of the distal cage, the bottom surface opposite the top surface,   the top and bottom distal ramps facilitating expansion of the expandable interbody in a lordotic direction and a cranial-caudal direction;   a top proximal ramp slidable along a top surface of the proximal cage;   a bottom proximal ramp slidable along a bottom surface of the proximal cage, the bottom surface opposite the top surface,   the top and bottom proximal ramps facilitating expansion of the expandable interbody in the cranial-caudal direction; and   a plurality of endplates in mechanical connection with the top distal ramp, the bottom distal ramp, the top proximal ramp, and the bottom proximal ramp,
 the plurality of endplates expandable in a medial-lateral direction, 
   the expandable interbody being diagonally symmetrical about a longitudinal axis of the expandable interbody.   
     
     
         17 . The expandable interbody of  claim 16 , further comprising a drive screw mechanically connecting the distal cage and the proximal cage. 
     
     
         18 . The expandable interbody of  claim 16 , wherein the plurality of endplates comprises four (4) endplates, each endplate comprising:
 a body extending between a proximal end and a distal end;   an extension at the proximal end for engaging with the proximal end of each endplate of a bottom pair of endplates;   a cut-out defined in a medial edge of the body.   
     
     
         19 . A method of expanding an expandable interbody, the method comprising:
 first translating a distal cage proximally towards a proximal cage to a first position to cause a plurality of endplates to expand in a medial-lateral direction relative to a longitudinal axis of the expandable interbody;   second translating the distal cage proximally towards the proximal cage from the first position to a second position different than the first position,   such that a locking hook of a top distal ramp clears a channel defined in a distal end of a first bottom endplate, and   such that a locking hook of a bottom distal ramp clears a channel defined in a distal end of a first top endplate;   the second translating causing:   the top distal ramp to slide along the distal cage to achieve a desired lordosis;   a first projection of the proximal cage to clear a channel defined in a proximal end of the first bottom endplate, and   a second projection of the proximal cage to clear a channel defined in a proximal end of a second bottom endplate;   third translating the distal cage proximally towards the proximal cage from the second position to a third position, a bore of the distal cage abutting a distal face of the proximal cage, the distal face of the proximal cage preventing further proximal translation of the distal cage; and   the third translating causing a top proximal ramp to slide along the proximal cage in a cranial-caudal direction,
 such that a protrusion of the first bottom endplate slides within a groove defined in a proximal extension of a second top endplate, thereby allowing the first bottom endplate to vertically separate from the second top endplate. 
   
     
     
         20 . The method of  claim 19 , wherein the first translating comprises:
 engaging internal threading of the distal cage with a distal end of a drive screw;   engaging internal threading of the proximal cage with a proximal end of the drive screw, the internal threading of the proximal cage being different than the internal threading of the distal cage; and   actuating the drive screw in a first direction, such that the distal cage is translated proximally towards the proximal cage.   
     
     
         21 . The method of  claim 19 , wherein firstly expanding a plurality of endplates in a medial-lateral direction comprises:
 sliding a proximal channel defined in the proximal end of the first bottom endplate along a projection of a bottom proximal ramp;   sliding a proximal channel defined in a proximal end of a second bottom endplate along a projection of the bottom proximal ramp;   sliding a proximal channel defined in a proximal end of the first top endplate along a projection of the top proximal ramp; and   sliding a proximal channel defined in a proximal end of the second top endplate along a projection of the top proximal ramp,   wherein the first bottom endplate and the second bottom endplate move away from each other, and   wherein the first top endplate and the second top endplate move away from each other.   
     
     
         22 . The method of  claim 19 , wherein the second translation comprises
 engaging a ramp of the distal cage with a ramp portion of the top distal ramp,   the ramp portion having opposing edges, each opposing edge comprising a straight portion and a curved portion at a distal end of the opposing edge, the curved portion abutting the distal cage and the straight portion not abutting the distal cage;   driving the distal cage proximally towards the proximal cage, such that the straight portion of the opposing edges of the ramp portion abuts the distal cage and the straight portion of the opposing edges is parallel to the ramp of the distal cage; and   moving the straight portion of the opposing edges along the distal cage, until the curved portion of the opposing edges extends beyond the distal cage,   the straight portion of the opposing edges remaining parallel to the ramp of the distal cage.